NEETChemistryClassification of Elements and Periodicity in Properties
Which of the following are correct? (i) First ionisation enthalpy of He < Second ionization enthalpy of Li. (ii) Li has the highest second ionisation enthalpy. (iii) All d -block elements are transition elements. (iv) The only alphabet not found in the periodic table is the letter ' J '. (v) Francium concentration is 10⁻¹⁸ ppm on Earth.
Options
- A(i), (ii), (iv)
- B(i), (ii), (iv), (v)
- C(i), (ii), (v)
- D(iv), (v)
Correct answer
B. (i), (ii), (iv), (v)
Step-by-step solution
All transition elements are d -block elements but all d -block elements are not transition metals. A transition metal is one which forms one or more stable ions which have incomplete d -orbitals. On the basis of this definition, scandium and zinc do not count as transition metal although they are d-block elements. Thus, statement (3) is incorrect.